The two largest application areas for carbon powders are rubber reinforcement using carbon blacks and filtration using activated carbon. Specialized carbon blacks are used as pigments or additives to render polymers electrically dissipative/conductive.
The raw materials for these carbon powders are rich in carbon and mainly fossil-based. Carbon blacks are entirely produced from heavy fossil oil fractions. The most common production method is the so called furnace black process in which the oil is dispersed to fine droplets and sprayed into a furnace where it is pyrolyzed at temperatures of about 1000° C. Activated carbons are produced mainly from solid fossil non-powdery raw materials such as lignite or hard coal. Lignocellulosic raw materials such as peat, wood and coconut shells are also used to some extent. Production of activated carbon consists of two steps: Carbonization at temperatures up to 1000° C. for removal of non-carbon elements and a second activation step in order to generate a high surface area.
Annually, about 105 Gigatons of lignocellulosic biomass is being produced corresponding to about 42 Gigatons of carbon. Lignocellulosic biomass could become an abundant raw material for carbon powder products. Carbonization of substrates is more efficient if the substrate is present as fine particles with a large surface area to the hot atmosphere. Carbon Black is produced by pyrolysis of fine fossil-based oil droplets. The main disadvantage with present techniques, which is being addressed in this invention, is that no method exists today for efficient carbonization of lignocellulosic raw material as a powder.
In the article “A Study on Synthesis and Characterization of Biobased Carbon Nanoparticles from Lignin”, Prasad Gonugunta et al, World Journal of Nano Science and Engineering, 2012, 2, 148-153 there is a disclosed a method for making carbon nanoparticles from lignin. Also in US20120269715 there is disclosed a method for making carbon particles from lignin.
There is however no process available for making carbonized particles or agglomerates by using a lignocellulosic material as a powder whereby this can be performed at a quick pace.
Thus there is a need for method for making carbonized lignocellulosic material as particles or agglomerates which is efficient.